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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Research in Plant Disease
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Journal DOI :
Korean Society of Plant Pathology
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Volume & Issues
Volume 17, Issue 3 - Dec 2011
Volume 17, Issue 2 - Aug 2011
Volume 17, Issue 1 - Apr 2011
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Characterization of Phytoplasmal Disease Occurred on Floricultural Crops in Korea
Chung, Bong-Nam ; Jeong, Myeong-Il ; Choi, Gug-Sun ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 265~271
DOI : 10.5423/RPD.2011.17.3.265
Seven phytoplasma diseases have been occurred on floricultural crops in Korea : Ph-ch1 and Ph-ch2 of chrysanthemum, Ph-lily of lily, petunia flat stem-Korean (PFS-K) of petunia, poinsettia branch inducing- Korean (PoiBI-K) of poinsettia, statis witches` broom-Korean (SWB-K) of statis and azalea witches broom (AWB). Classification of the seven phytoplasmal diseases based on 16S ribosomal RNA (rRNA) sequences showed that floricultural crop phytoplasma disease were widespread in order of aster yellow (AY), stolbur and X-disease in Korea. In phenotypic characters, the fasciation was occurred in both monocotyledon plant of lily and dicotyledon plants of petunia and poinsettia. Besides, the fascination was occurred in Ph-lily of stolbur, petunia PFS-K of AY and PoiBI-K of X-disease. This result indicated that phytoplasma classification based on 16S rRNA and symptoms are not consistently related. The comparison of 16S rRNA sequence of the seven floricultural crop phytoplasma with five tree phytoplasmal diseases of jujube witches` broom, paulownia witches` broom, wild jujube witches` broom, mulberry dwarf, golden rain phytoplasma occurred in Korea showed as high as 88.5-99.9% homology. Among them, especially mulberry dwarf showed the highest homology with the seven floricultural crop phytoplasms. Based on this result, floricultural crop phytoplasmas were assumed to be transmitted by insect vectors from tree phytoplasmas in Korea.
Natural Occurrence of Fusarium Head Blight and Its Mycotoxins in 2010-harvested Barley and Wheat Grains in Korea
Ryu, Jae-Gee ; Lee, Soo-Hyung ; Son, Seung-Wan ; Lee, Seung-Ho ; Nam, Young-Ju ; Kim, Mi-Ja ; Lee, Theresa ; Yun, Jong-Chul ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 272~279
DOI : 10.5423/RPD.2011.17.3.272
Fusarium species are worldwide causal agents of Fusarium head blight (FHB) in cereals such as barley and wheat. Their toxigenic potential is a health risk for both humans and animals. To survey the natural occurrence of FHB and mycotoxins produced by Fusarium, total 126 barley or wheat grains grown in 2009-2010 season in Korea were collected. The incidence of FHB was 30.7% in silage barley, 26.9% in wheat, 20.7% in naked barley, 19.4% in malting barley, 16.4% in unhulled barley. Overall FHB incidence of barley and wheat in 2010 was 23.0% and 10% higher than that of 2009. The incidences and level of deoxynivalenol (DON), nivalenol (NIV), and zearalenone (ZEA) were 34%, 0.89 mg/kg, 84.9%, 1.86 mg/kg, and 10.3%, 0.06 mg/kg respectively. The both levels and incidences of NIV were found to be highest in barley, whereas the level of DON was found to be highest in wheat. Incidences of DON and NIV and the level of NIV in the samples from southern regions of Korea were higher than those from central region, whereas the level of DON from central region was higher than that from southern regions. This is the first paper demonstrating regional difference in natural occurrence of DON and NIV in wheat and barley.
Toxigenic Fungal Contaminants in the 2009-harvested Rice and Its Milling-by products Samples Collected from Rice Processing Complexes in Korea
Son, Seung-Wan ; Nam, Young-Ju ; Lee, Seung-Ho ; Lee, Soo-Min ; Lee, Soo-Hyung ; Kim, Mi-Ja ; Lee, Theresa ; Yun, Jong-Chul ; Ryu, Jae-Gee ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 280~287
DOI : 10.5423/RPD.2011.17.3.280
This investigation was undertaken to survey toxigenic fungal contamination of various rice samples in 93 rice processing complexes (RPC) in Korea. Rice was grown in 2009 and the samples were collected in 2010. Seven types of rice samples such as unhusked, brown, blue-tinged, discolored, polished, half-crushed, and rice husks were obtained from each RPC. One-hundred and five grains of each sample were placed on PDA plates after surface disinfection. The incidence of fungal contaminants was 26.8%. Aspergillus spp. was the most dominant fungal contaminants and Fusarium spp. was the most frequently occurred in samples. The heaviest Fusarium contamination was found in unhusked grain, rice husks, and bare blue-tinged rice and followed by colored rice whereas broken rice was the least contaminated. Regional difference of fungal contamination was distinctive. Fusarium incidence in the rice samples from southern region of Korea including Jeolla and Gyeongsang Provinces was higher than those from central region including Chungcheong, Gyeonggi, and Gangwon Provinces. In contrast to Fusarium spp., Aspergillus spp. and Penicillium spp. were dominated in brown and polished rice samples and their incidences were more severe in central region than southern region. The major contaminants shown more than 1% of kernels infected were Aspergillus (5.0%), Fusarium (2.0%), Alternaria (1.4%), Dreschlera (1.3%), Penicillium spp. (1.3%), and Nigrospora spp. (1.0%). Collectotrichum, Pyricularia, Myrothecium, Epicoccum, Cladosporium, Moniliella, Gloeocercospora, Chaeto- mium, Curvularia, Phialopora, Acremonium, Gliomastix, Trichoderma, Rhizopus, Phomopsis, Paecilomyces, Genicularia, Geotrichum, Acremoniella, Rhizoctonia, Phoma, Oidiodendran, and Candida spp. were among the rest observed at low incidence. The major contaminants of rice samples were well-known as toxigenic fungal genera so toxin producibility of these fungal isolates is necessary to be examined in future. It is also needed to study Myrothecium spp. on species level as it was detected for the first time in rice.
Development of In Vitro Seedling Screening Method for Selection of Resistant Rice Against Bakanae Disease
Lee, Yong-Hwan ; Lee, Myeong-Ji ; Choi, Hyo-Won ; Kim, Sung-Taek ; Park, Jin-Woo ; Myung, Inn-Shik ; Park, Kyung-Seok ; Lee, Se-Weon ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 288~294
DOI : 10.5423/RPD.2011.17.3.288
Rice bakanae disease, caused by the fungus Fusarium fujikuroi, is one of the most important rice diseases and distributed widely in Asia. Resistance screening system in rice field had been established. However, the evaluation results of the system vary according to the environmental conditions when the test is conducted. To develop precise and rapid evaluation method of disease resistance of rice to bakanae disease, in vitro screening system was attempted in this study. The six cultivars namely, `Nampyeongbyeo`, `Junambyeo`, `Chucheongbyeo`, `Samcheonbyeo`, `Odaebyeo` and `Hwasinbyeo` were tested. They were planted onto MS agar medium (10 ml) in test tube (
) and incubated at
in growth chamber under 12 hr light condition. Symptoms of over growth appeared a few days after seeding and then seedling were withered 2-3 weeks after over growth. The disease symptoms such as leaf dryness on top of rice were appeared in the `Nampyeongbyeo` from 28 days at the concentration of
spores/ml culturing at
and then withered completely 35 days after seeding. Whereas the other varieties withered entirely 19-23 days after seeding. Using the in vitro seedling screening method, 72 rice varieties were investigated to select resistant cultivar. Finally, two resistant cultivars (`Nampyeongbyeo` and `Inwolbyeo`) and seven moderately resistant cultivars (`Hwadongbyeo`, `Seokjeongbyeo`, `Samgwangbyeo`, `Sampyeongbyeo`, `Nonghobyeo`, `Heukjinjubyeo` and, `Joanbyeo`) were selected. If in vitro seedling screening method was used for evaluation of bakanae disease resistance, it would be completed within 35 days after sowing of rice seed.
Fungicide Spray Program to Reduce Application in Anthracnose of Strawberry
Nam, Myeong-Hyeon ; Kim, Hyeon-Suk ; Nam, Yun-Gyu ; Peres, N.A. ; Kim, Hong-Gi ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 295~301
DOI : 10.5423/RPD.2011.17.3.295
The effect of various fungicides on anthracnose of strawberry, caused by Colletotrichum gloeosporioides, was determined in vitro, and in greenhouse and field trials. The
values of benomyl were clearly different between two sensitive and resistant groups of isolates. Iminoctadine tris had lower
values than mancozeb and propineb as protective fungicides and the response of mancozeb, propineb and azoxystrobin was variable depending on the isolate. In the greenhouse, pre- and post- inoculation fungicide applications significantly reduced disease compared to the non-treated control. Propineb, mancozeb and azoxystrobin were effective in controlling the disease when applied prior to inoculation. Metconazole and prochloraz-Mn treatments as ergosterol biosynthesis-inhibiting fungicides had the lowest incidence of anthracnose. In the nursery field trials in 2009 and 2010, the reduced fungicide spray program provided similar levels of disease control compared to the calendar-based applications with captan. A reduced spray program based on efficacious fungicides such as prochloraz-Mn will be useful for strawberry growers and provide more options for controlling anthracnose in Korea.
Suppression Effect and Mechanism of Citrus Scab in the Citrus Pre-inoculated with Rhizobacterial Strains
Kim, So-Yeon ; Hyun, Jae-Wook ; Jeun, Yong-Chull ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 302~310
DOI : 10.5423/RPD.2011.17.3.302
Elsinoe fawcettii is one of major pathogenic fungi which cause citrus scab diseases, resulting in fruit blemishes that reduce the economic value of fruit. By increasing interest to safe products of crops, the alternative methods of disease control is highly required. We investigated whether the 215 bacterial strains isolated from Jeju Island possess antifungal effect or suppression effect on the symptom development by Elsinoe fawcettii on citrus. Among them, three bacterial strains THJ 609-3, MRL408-3, and TRH423-3 that exhibited antifungal capacity against Elsinoe fawcettii were selected. To illustrate the disease suppression mechanism, pre-inoculation with the selected bacterial strains was carried out whether could suppress the citrus crab on the leaves. The observation with a fluorescence microscope revealed that the selected bacteria could decrease the number of fungal spores. The ratio of germ tube formation was also decreased by the selected bacterial strains at one day after fungus challenge. The strain THJ 609-3 was identified as Pseudomonas putida as a result of analyzing the internal transcript spaces of the rhizobacterial rDNA. The strains MRL 408-3 and TRH 423-3 were identified as Burkholderia gladioli. Our results may be valuable when the selected rhizobacterial strains used as the environment-friendly microbe for biological control on citrus scab caused by Elsinoe fawcettii.
Development of Resistance Evaluation Method for Powdery Mildew (Leveillula taurica) in Capsicum spp.
Kim, Su ; Kim, Dong-Hwi ; Kim, Dae-Hyun ; Han, Kyung-Sook ; Han, You-Kyoung ; Lee, Seong-Chan ; Cho, Myeong-Cheoul ; Yang, Eun-Young ; Kim, Kee-Hong ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 311~316
DOI : 10.5423/RPD.2011.17.3.311
Pepper powdery mildew causes increasingly economical damage due to increased cultivation of pepper in greenhouses. To assess resistance of pepper resources against pepper powdery mildew, we developed a novel evaluation formula for pepper resistance against powdery mildew. The evaluation formula named S index is as follows; (number of the highest disease leaf/top leaf number)-(number of the lowest disease leaf/top leaf number). Positive correlation (81%, P
Influence of Disease Severity of Bacterial Pustule Caused by Xanthomonas axonopodis pv. glycines on Soybean Yield
Hong, Sung-Jun ; Kim, Yong-Ki ; Jee, Hyeong-Jin ; Shim, Chang-Ki ; Kim, Min-Jeong ; Park, Jong-Ho ; Han, Eun-Jung ; Lee, Bong-Choon ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 317~325
DOI : 10.5423/RPD.2011.17.3.317
Bacterial pustule of soybean (Glycine max) caused by Xanthomonas axonopodis pv. glycines is one of the most prevalent bacterial diseases of soybean in Korea, where it causes considerable yield loss. This study was carried out to develop yield prediction model for bacterial pustule by analyzing correlation between the percentage of diseased leaf area and yield. The severe disease incidence of soybean bacterial pustule caused yield losses by 19.8% in 2006 and 16.8% in 2007, respectively. Severity of bacterial pustule greatly affected on 100 seed weight and yield, but did not on stem length, number of branches per plant, number of pods per plant, number of seeds per plant. On the other hand, correlation coefficients between diseased leaf area and yield were
(`07), respectively. The regression equation obtained by analyzing correlation between the percentage of diseased leaf area and yield loss in 2006 and in 2007 was y
Disease Responses of Tomato Pure Lines Against Ralstonia solanacearum Strains from Korea and Susceptibility at High Temperature
Lee, Hyoung-Ju ; Jo, Eun-Jeong ; Kim, Nam-Hee ; Chae, Young ; Lee, Seon-Woo ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 326~333
DOI : 10.5423/RPD.2011.17.3.326
This study evaluated disease resistance responses of pure lines of tomato plants at various temperature conditions against Ralstonia solanacearum strains isolated from Korea. Evaluation of six tomato lines with various strains of R. solanacearum showed that many strains can infect the resistant lines of tomato plants previously known as highly tolerant to bacterial wilt. One of the most virulent strains, SL341 (race 1 and biovar 4) caused severe infection on all six tomato lines, irrespective of temperature. In contrast, a moderately virulent strain SL1944 (race 1, biovar 4) showed the remarkable difference in disease progress on some resistant lines dependent on temperature. Moneymaker and Bonny Best were susceptible to SL1944 at all tested conditions with different temperature. However, tomato lines, such as Hawaii 7998, Hawaii 7996, Bblocking which were previously known as highly tolerant lines, were severely infected by SL1944 at relatively higher temperature (
for 14 hr light and
for 10 hr dark cycle). The disease progress at high temperature was much faster than those at low temprature on the same tomato line and those on Moneymaker and Bonny Best at the same high temprature. This result suggested that R. solanacearum strains isolated in Korea were highly virulent to bacterial wilt resistant tomato lines and some strains may cause severe infection on those plants at higher temperature.
Occurrence of Virus Diseases on Major Crops in 2010
Kim, Jeong-Soo ; Lee, Su-Heon ; Choi, Hong-Soo ; Kim, Mi-Kyeong ; Kwak, Hae-Ryun ; Nam, Mun ; Kim, Jeong-Sun ; Choi, Gug-Seoun ; Cho, Jeom-Deog ; Cho, In-Sug ; Chung, Bong-Nam ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 334~341
DOI : 10.5423/RPD.2011.17.3.334
The kinds of crop requested from agricultural actual places of famers, Agricultural extension services and so forth was 8 including red pepper for vegetables, 4 including apple for fruit trees and 6 including chrysanthemum for flowers in 2010. The important vegetables in clinical diagnosis of viral diseases were tomato, watermelon and red pepper having the requested rate of 31.8%, 21.4% and 19.5%, respectively. On fruit trees, grape and apple were most common with the requested rate of 63.6% and 33.0%, orderly. On floral crops, tulip and cactus were damaged by viral diseases with the requested rate of 60.0% and 20.0%, orderly. On peppers and tomatoes, six viruses including Cucumber mosaic virus (CMV) and Broad bean wilt virus 2 (BBWV2) infected. Five viruses including Melon necrotic spot virus (MNSV) and CMV were identified from watermelons. On grapes, six viruses including Grapevine fleck virus (GFkV) infected. CMV was identified from six vegetables including pepper out of 8 kinds of vegetables and tulip plant. Total agents of virus and viroid species were 32 and 4 species, respectively, in 2010. Tomato yellow leaf curl disease by Tomato yellow leaf curl virus and Tobacco yellow leaf curl virus was occurred newly at 18 Si/Gun areas including Buan, Jeonbuk province in 2010 and the total areas were increased up to 58 Si/Gun from the first incidence in 2008. Tomato spotted wilt virus (TSWV) occurred newly at two areas of Jinan, Jeonbuk and Jeju in Jeju province in 2010, and the incidence areas were expanded to 25 Si/Gun areas from severe occurrence at Anyang area in 2004. No incidence of TSWV was recorded only in Gyeongbuk and Chungbuk province. Tomato bushy stunt virus occurred newly at Jinju, Gyeongnam, and it had the total incidence areas of 5 Si/Gun after first observation at Sacheon, Gyeongnam in 2004.
Virus Disease Incidences and Transmission Ecology of Oriental Melons in Seongju Area
Park, Seok-Jin ; Lee, Joong-Hwan ; Nam, Moon ; Park, Chung-Youl ; Kim, Jeong-Seon ; Lee, Joo-Hee ; Jun, Eun-Suk ; Lee, Jun-Seong ; Choi, Hong-Soo ; Kim, Jeong-Soo ; Moon, Jae-Sun ; Kim, Hong-Gi ; Lee, Su-Heon ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 342~350
DOI : 10.5423/RPD.2011.17.3.342
Throughout the years 2008 to 2010, we analyzed approximately two thousand oriental melon samples collected from Seongju, using electron microscopy and testing by RT-PCR using primers specific for eight cucurbit-infecting viruses. Data from RT-PCR indicated that Cucumber green mottle mosaic virus (CGMMV), Watermelon mosaic virus 2 (WMV2) and Zucchini yellow mosaic virus (ZYMV) were present and the other viruses were not detected. Among them, CGMMV and WMV2 were the most prevalent pathogens. CGMMV was thought to infect oriental melon from the early growing season, and reached nearly 100% in the later of growing period. Otherwise, WMV2 emerged from June, several months later compared to CGMMV. CGMMV was detected from all aerial parts of the oriental melon including seeds, but not from the roots of the grafted pumpkin rootstock. Seed of two out of five commercial varieties were shown to be CGMMV positive. Nine varieties of pumpkins used as rootstocks were not infected with CGMMV. When the seedlings of grafted oriental melon were transplanted into pots mixed with the oriental melon debris infected with CGMMV, they were not infected by CGMMV. Cutting of pruning shear and the contact of tendrils contributed 48% and 30% to the transmission of the virus, respectively.
Analysis of the Occurrence of Rice stripe virus in Jeonnam Province
Ko, Sug-Ju ; Kang, Beom-Ryong ; Kim, Do-Ik ; Choi, Duck-Soo ; Kim, Seon-Gon ; Lee, Gwan-Seok ; Kim, Chang-Seok ; Choi, Hong-Soo ; Kim, Hong-Jae ; Kim, Jeong-Soo ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 351~357
DOI : 10.5423/RPD.2011.17.3.351
Occurrence of Rice stripe virus (RSV) was investigated in Jeonnam province from 2008 to 2011. Incidence of RSV was surveyed in paddy fields during growth stage. In western and southern coast parts of 5 districts, Jindo, Wando, Shinan, Haenam and Muan, rice was severely damaged by RSV from 2008 to 2009. But, RSV didn`t almost occur in 2010. Viruliferous ratio (VIR) of RSV from overwintered small brown plant hopper (SBPH, Laodelphax striatellus) showed 4.7%, 11.3%, 8.7%, and 2.8% from 2008 to 2011. It was highly recorded in Jindo, Wando, and Shinan of southwestern area. SBPH was collected by sucking machine at 1
with 3 replications per paddy field in March. The density of SBPH was high on March, but low on April in non-cultivated barley field from winter to spring. Farmer`s plowing this season assumed to be a cause of SBPH density decrease. The number of SBPH was 7.7, 5.4, and 4.0 per
during three years, respectively.
Hop stunt viroid (HSVd) Sequence Variants from Dapple Fruits of Plum (Prunus salicina L.) in Korea
Cho, In-Sook ; Chung, Bong-Nam ; Cho, Jeom-Doeg ; Choi, Seung-Kook ; Choi, Gug-Seoun ; Kim, Jeong-Soo ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 358~363
DOI : 10.5423/RPD.2011.17.3.358
Dapple fruits of plum cv. Oiishiwase (Prunus salicina L.) were occurred at Gyeonggi-do and Gyeongsangbukdo. The symptoms resembled the dapple fruit disease caused by Hop stunt viroid (HSVd). To identify the causal disease agents, RT-PCR was performed with the specific primers of HSVd. RT-PCR analysis showed that HSVd variants (DP1, DP2) were detected from dapple fruits. HSVd detection was also confirmed by the dot blot hybridization using a DIG-probe specific to HSVd. Nucleotide sequences of DP1 and DP2 had the identities of 94-100% with those of other 7 variants of HSVd in Genbank database. DP1 and DP2 were different in two nucleotides of CG and AA at position of 59 and 60, orderly. Based on nucleotide sequences at position of 59 and 60, HSVd variants associated with plum dapple fruits could be divided mainly into three groups as CG, AA and TG.
Gray Mold on Carrot Caused by Botrytis cinerea in Korea
Park, Kyeong-Hun ; Ryu, Kyoung-Yul ; Yun, Hye-Jeong ; Yun, Jeong-Chul ; Kim, Byeong-Seok ; Jeong, Kyu-Sik ; Kwon, Young-Seok ; Cha, Byeong-Jin ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 364~368
DOI : 10.5423/RPD.2011.17.3.364
Gray mold caused by Botrytis cinerea was found on a carrot seedling in a greenhouse and a field at Daegwallryeong, Gangwon Province in 2007-2009. Symptoms included irregular, brown, blight, or chlorotic halo on leaves and petioles of the carrots. Fungal conidia were globose to subglobose or ellipsoid, hyaline or pale brown, nonseptate, one celled,
) in size, and were formed on botryose heads. B. cinerea colonies were hyaline on PDA, and then turned gray and later changed dark gray or brown when spores appeared. The fungal growth stopped at
, temperature range for proper growth was
on MEA and PDA. Carrots inoculated with
ml conidial suspension were incubated in a moist chamber at
for pathogenicity testing. Symptoms included irregular, brown, water-soaked rot on carrot roots and irregular, pale brown or dark brown, water-soaked rot on leaves. Symptoms were similar to the original symptoms under natural conditions. The pathogen was reisolated from diseased leaves, sliced roots, and whole roots after inoculation. As a result, this is the first report of carrot gray mold caused by B. cinerea in Korea.
Detection of Fusarium verticillioides Contaminated in Corn Using a New Species-specific Primer
Kang, Mi-Ran ; Kim, Ji-Hye ; Lee, Seung-Ho ; Ryu, Jae-Gee ; Lee, Theresa ; Yun, Sung-Hwan ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 369~375
DOI : 10.5423/RPD.2011.17.3.369
Fusarium verticillioides (teleomorph: Gibberella moniliformis), a member of the Gibberellea fujikuroi species complex, causes rots of corn stalks and ears, and produces a group of mycotoxins known as fumonisins that are harmful to animals and humans. Here, we focus on the development of a species-specific PCR primer set for differentiating F. verticillioides from other fumonisin-producing Fusarium species belonging to the species complex, such as F. proliferatum, F. fujikuroi, and F. subglutinans that are frequently associated with corn. The specific primers (RVERT1 and RVERT2) derived from the nucleotide sequences of RNA polymerase II beta subunit (RPB2) gene amplified a 208 bp-DNA fragment from only F. verticillioides isolates among the potential fumonisin-producing species examined; all of these isolates were shown to carry FUM1 required for fumonisin biosynthesis. The PCR detection limit using this specific primer set was approximately 0.125 pg/
genomic DNA of F. verticillioides. In addition, the F. verticillioides-specfic fragment was successfully amplified from genomic DNAs of corn samples contaminated with Fusarium spp. This primer set would provide a useful tool for the detection and differentiation of potential fumonisin-producing F. verticillioides strains in cereal samples.
Development and Evaluation of PCR-Based Detection for Pseudomonas syrinage pv. tomato in Tomato Seeds
Cho, Jung-Hee ; Yim, Kyu-Ock ; Lee, Hyok-In ; Yea, Mi-Chi ; Cha, Jae-Soon ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 376~380
DOI : 10.5423/RPD.2011.17.3.376
The bacterial speck of tomato caused by Pseudomonas syringae pv. tomato leads to serious economic losses especially on fruits of susceptible genotype. Thus, Pseudomonas syringae pv. tomato is a plant quarantine bacterium in many countries including Korea. In this study, we developed specific PCR assays for detection of the bacterium from tomato seeds. A specific primer set is designed from the hrpZ gene for specific detection of Pseudomonas syringae pv. tomato. A 501 bp PCR product corresponding to hrpZ gene was amplified only form Pseudomonas syringae pv. tomato strains, but no PCR product was amplified from other tomato bacterial pathogens, such as Pseudomonas syringae pv. glycinea, P. syringae pv. maculicola, P. syringae pv. atropurpurea, P. syringae pv. morsprunorum, and from other P. syringae pathovar strains. The nested-PCR primer set corresponding to an internal fragment of the 501 bp sequence (hrpZ) gine was used to specific detection of Pseudomonas syringae pv. tomato in tomato seed. A 119 bp PCR product using nested PCR primer was highly specific and sensitive to detect low level of Pseudomonas syrigae pv. tomato in tomato seeds. We believe that the PCR assays developed in this study is very useful to detect Pseudomonas syringae pv. tomato from the tomato seeds.
Influence of Environmental Factors on Conidial Germination of Alternaria dauci
Park, Kyeong-Hun ; Yun, Hye-Jeong ; Ryu, Kyoung-Yul ; Yun, Jeong-Chul ; Kim, Se-Ri ; Kim, Won-Il ; Kim, Doo-Ho ; Kwon, Young-Seok ; Cha, Byeong-Jin ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 381~385
DOI : 10.5423/RPD.2011.17.3.381
Effects of temperatures, relative humidity, pH, and dry periods on conidial germination of Alternaria dauci were evaluated under in vitro conditions. Conidial germination was accelerated at over 95% relative humidity in
condition. Conidial germination was rapidly reduced at 5 regardless of relative humidity conditions. More than 50% of the conidial germination were initiated within 2 h at
through pH 5 to 7. The highest conidial germination of A. dauci was on 0.2% of carrot leaf extract. Conidia could survive longer than 12 h, even though its germination decreased. After a 12 h dry period, around 10% of conidia revived and germinated when conidia were hydrated again. These results could be used as the useful information on conidial germination of A. dauci and ecology of Alternaria leaf blight.
Occurrence of Downy Leaf Spot on Juglans regia Caused by Microstroma juglandis in Korea
Lee, Sang-Hyun ; Lee, Seung-Kyu ; Park, Ji-Hyun ; Cho, Sung-Eun ; Shin, Hyeon-Dong ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 386~390
DOI : 10.5423/RPD.2011.17.3.386
In June 2011, walnuts (Juglans regia) from orchards in Kimcheon and Muan, in southern Korea, were found to exhibit downy mildew-like symptoms of a foliar disease. Whitish polygonal efflorescence was produced on the abaxial surface of affected leaves and discolored light green blotches on the corresponding adaxial surfaces. In the later stage of disease development, diseased tissues collapsed and became necrotic. Based on morphological and cultural characteristics, the causal fungus was identified as Microstroma juglandis. The sequence of ITS rDNA of the present isolate showed 100% similarity with those of M. juglandis obtained from GenBank databases, thus confirming its identity. Pathogenicity tests were conducted on leaves of walnut seedlings, fulfilling Koch`s postulates. The disease has been previously reported in North America, Europe, Oceania and some western Asia. This is the first report of downy leaf spot on walnuts in East Asia.
Confirmation of the Presence of Pleochaeta shiraiana Associated with Powdery Mildew of Celtis sinensis in Korea
Lee, Seung-Kyu ; Lee, Sang-Hyun ; Cho, Sung-Eun ; Park, Ji-Hyun ; Shin, Hyeon-Dong ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 391~395
DOI : 10.5423/RPD.2011.17.3.391
The presence of Pleochaeta shiraiana associated with powdery mildew of Celtis sinensis in Korea is dubious, mainly due to incomplete records of earlier workers. To confirm the occurrence of the powdery mildew and the identity of the causal fungus, morphological characteristics of the anamorph and teleomorph from nine samples deposited in KUS (Herbarium in Korea University) were examined by light microscopy. Identification of the fungus was supported by comparing four ITS sequences from Korean samples with two Japanese data. This is the first confirmed report of the powdery mildew associated with P. shiraiana in Korea.
Occurrence of Soft Rot on Raspberry (Rubus crataegifolius) Caused by Rhizopus oryzae in Korea
Kwon, Jin-Hyeuk ; Kang, Dong-Wan ; An, Jae-Uk ; Choi, Ok-Hee ; Kwak, Youn-Sig ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 396~398
DOI : 10.5423/RPD.2011.17.3.396
Soft rot disease on Raspberry (Rubus crataegifolius Bunge) was observed in sale boxes at Jinju City Wholesale Market of Agricultural Products in June 2010. The infected fruits were rapidly water-soaked, softened, black and eventually rotted. The colonies on the infected fruits were white to light brown, formed numerous sporangiospores. Optimum temperature for the mycelial growth of the causal fungus on PDA was
and growth was still apparent at
. Sporangia were globose, white at early and gradually to black, and 40-210
in diameter. Sporangiophores were white to mid brown as maturation and 8-20
in diameter. Columella were globose to sub-globose, and the size of the diameter was 85-120
in diameter. Sporangiospores were sub-globose, rhomboidal and irregular, streaked and 5-10
in length. On the basis of symptom, mycological characteristics, ITS rDNA sequence analysis, and pathogenicity of the fungus, the causal fungus was clearly identified as Rhizopus oryzae Went & Prinsen Geerligs. This is the first report of soft rot by R. oryzae on R. crataegifolius in Korea.
Stem Rot of Stachys sieboldii Caused by Sclerotium rolfsii in Korea
Kwon, Jin-Hyeuk ; Kang, Dong-Wan ; Lee, Seong-Tae ; Choi, Ok-Hee ; Shen, Shun-Shan ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 399~401
DOI : 10.5423/RPD.2011.17.3.399
Stem rot of Stachys sieboldii occurred sporadically in the farmer`s fields at Shindeung-myeon, Sancheonggun, Gyeongnam province in Korea. The infected leaves and stems are water-soaked, rotted, wilted and finally leads to the death of the whole plants. The sclerotia, 1-3 mm, white to brown, globoid, were formed on lesions and the surface of soil line. The optimum temperature for mycelial growth and sclerotia formation was
on potato dextrose agar. The typical clamp connections were observed in the hyphae of the fungus. On the basis of mycological characteristics and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report of stem rot on S. sieboldii caused by S. rolfsii in Korea.
Sclerotium blight of Phalaenopsis Orchids Caused by Sclerotium rolfsii in Korea
Han, Kyung-Sook ; Lee, Seong-Chan ; Han, You-Kyoung ; Kim, Su ; Park, Jong-Han ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 402~404
DOI : 10.5423/RPD.2011.17.3.402
The Sclerotium blight was found on Phalaenopsis spp. at Dong-du-cheon city, and Hwa-seong city, Gyenggido, Korea in September 2009. The symptom included yellowing on lower leaves and wilt of a whole plant. Severely infected plants were blighted and died eventually. White mycelial mats appeared on the surface of basal stem and bulbs and the sclerotia were formed on stems, roots, and sphagnum moss. The sclerotia were spherical, 1-3 mm and white to brown. The optimum temperature for the growth and sclerotia formation was
on PDA. On the pathogenicity test, the first symptom appeared 5 days after inoculation and developed to severe stem rot and blight. On the basis of mycological characteristics and pathogenicity, the causal fungus was identified as Sclerotium rolfsii. This is the first report on the sclerotium blight on Phalaenopsis spp. caused by Sclerotium rolfsii in Korea.
Rhizoctonia Blight of Azolla japonica Caused by Rhizoctonia solani
Lee, Jung-Han ; Cha, Jea-Yul ; Noh, Gil-Han ; Han, Ki-Soo ; Bae, Dong-Won ; Kwon, Young-Sang ; Lim, Chae-Shin ; Jeong, Sung-Woo ; Kwon, Jin-Hyeuk ; Park, Chung-Gyoo ; Kwak, Youn-Sig ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 405~409
DOI : 10.5423/RPD.2011.17.3.405
Azolla Lam. is a small aquatic fern with deeply bilobed leaves, which are consisted of a thick greenish, with chlorophyll, upper (dorsal) lobe and a thinner, translucent lower (ventral) lobe, without chlorophyll, submerged in the water. Azolla blight was observed at a lotus pond. Mycological characteristics of the fungus associated with Azolla blight was immediately determined as Rhizoctonia sp. by the thickness and branching of hypha at right angles at the point toward the distal end of septa, with branching hypha is constricted. The fungus produced brown mycelia and dark brown sclerotia on PDA. The optimum temperature for mycelial growth and sclerotia formation were
, respectively. The optimum temperature for fungal infection was
, when spray inoculated. Phylogenetic analysis of rDNA-ITS revealed that the fungus was identified as Rhizoctonia solani (AG-1 IA) closest to one causing rice sheath blight disease. This is the first report on the blight disease of Azolla caused by R. solani in Korea.
Efficacy of Fungicides for the Control of Leaf Spots on Eriobotrya japonica and Photinia glabra
Seo, Sang-Tae ; Shin, Chang-Hoon ; Ji, Kwon-Hyeok ; Park, So-Young ;
Research in Plant Disease, volume 17, issue 3, 2011, Pages 410~412
DOI : 10.5423/RPD.2011.17.3.410
Since the late 2000s, a serious Entomosporium leaf spot disease, caused by Entomosporium mespili, has been found frequently on leaves of Eriobotrya japonica and Photinia glabra at a nursery station in Goheung and Jeju, respectively. Studies were conducted to select fungicides that would effectively control Entomosporium leaf spot. Among the three fungicides tested, weekly foliar applications of propiconazole and chlorothalonil effectively reduced disease severity on E. japonica and P. glabra showing control value of 64.1% and 87.6%, respectively. Weekly treatments of thiopanate methyl were less effective. Propiconazole controlled the disease, but, it was phytotoxic to P. glabra.